共查询到20条相似文献，搜索用时 31 毫秒
1.
Mineralogy and geochemistry of banded iron formation and iron ores from eastern India with implications on their genesis 总被引：1，自引：0，他引：1
The geological complexities of banded iron formation (BIF) and associated iron ores of Jilling-Langalata iron ore deposits,
Singhbhum-North Orissa Craton, belonging to Iron Ore Group (IOG) eastern India have been studied in detail along with the
geochemical evaluation of different iron ores. The geochemical and mineralogical characterization suggests that the massive,
hard laminated, soft laminated ore and blue dust had a genetic lineage from BIFs aided with certain input from hydrothermal
activity. The PAAS normalized REE pattern of Jilling BIF striking positive Eu anomaly, resembling those of modern hydrothermal
solutions from mid-oceanic ridge (MOR). Major part of the iron could have been added to the bottom sea water by hydrothermal
solutions derived from hydrothermally active anoxic marine environments. The ubiquitous presence of intercalated tuffaceous
shales indicates the volcanic signature in BIF.
Mineralogical studies reveal that magnetite was the principal iron oxide mineral, whose depositional history is preserved
in BHJ, where it remains in the form of martite and the platy hematite is mainly the product of martite. The different types
of iron ores are intricately related with the BHJ. Removal of silica from BIF and successive precipitation of iron by hydrothermal
fluids of possible meteoric origin resulted in the formation of martite-goethite ore. The hard laminated ore has been formed
in the second phase of supergene processes, where the deep burial upgrades the hydrous iron oxides to hematite. The massive
ore is syngenetic in origin with BHJ. Soft laminated ores and biscuity ores were formed where further precipitation of iron
was partial or absent. 相似文献
2.
3.
江西新余铁矿田铁矿成矿地质特征与成因分析 总被引：3，自引：0，他引：3
本文总结了新余铁矿田矿层和含铁岩系变化特征、矿层顶板、底板和含铁岩系标志层特征以及矿田东、中、西段构造特征,分析了铁矿的沉积成岩作用以及构造演化历史,解释了新余铁矿田的各种成矿地质特征,并运用系统分析方法和历史分析方法说明矿田成矿地质系统的内在规律,认为该矿床属于火山-沉积变质铁矿,其物质成分较稳定,体现出规律性的变形... 相似文献
4.
有关长江下游中生代晚期火山岩系中铁矿的若干问题 总被引：2，自引：0，他引：2
引言长江下游南京-芜湖(宁芜)和庐江-枞阳(庐枞)两个中生代晚期火山岩盆地中的铁矿,经过近年来各部门的地质队伍、科研单位及院校的详细工作,基本上查明了矿床的赋有状态、蚀变特征、矿石特点和成矿的主要控制因素,并在宁芜地区根据各种类型铁矿床之间的成因联系,建立了“玢岩铁矿”模式。虽然对“玢岩模式”的名称还有不同意 相似文献
5.
Theories proposed for the origin of large-scale crossbeds may be generalised into two main categories. The first suggests the large sigmoidal shape of the sediment layers results from variable differential compaction during and after deposition, whereas the second infers that the high angle of the crossbeds is the result of primary depositional processes.Britten (1983) has proposed that large-scale inclined strata may be produced according to his cide model whilst Mallett (1983) has suggested that such structures are produced by channel automigration. Parbury (1976) and Conaghan (1981), both proponents of the primary depositional model, interpret the large-scale inclined strata as foreset beds of a Gilbert-type delta prograding into deep (50 m water depth) lakes within which floating islands produce allochthonous deposits from hydroponic vegetation. Marchioni (1976, 1982), however, envisages that the large-scale inclined strata are epsilon crossbeds which have tilted during differential subsidence of peat swamps over which active channel systems have encroached.Nine kilometers of almost continuous high wall exposures have been studied in the Moura-Kianga Coal Mine of the southeastern Bowen Basin and it is concluded that none of the above-mentioned processes can explain the present configuration of sedimentary layering observed in these high walls at the Moura-Kianga Coal Mine. It is proposed that there the high-angle large-scale inclined strata have originated as primary features associated with a crevasse sub-delta. Subsidence in excess of vegetation accumulation within the peat swamp provides the mechanism whereby a shallow lake developed and into which a crevasse sub-delta was deposited. Similar processes have been described by Coleman and Prior (1980) from the Mississippi delta. 相似文献
6.
The degree sheet Aeromagnetic maps up to 17‡N, acquired from the Geological Survey of India, have been manually redigitised
at 6 minute intervals to study the long wavelength anomalies over peninsular India. These data have been collected at different
survey altitude, epochs, flight line directions, etc. Great care has been taken to correct the total field map and remove
the contribution due to the core field and prepare an accurate crustal anomaly map. For the first time, a regional map, depicting
the NW-SE structural features north of the orthopyroxene isograd with the essentially E-W features to the south of it and
revealing several well known structures, is presented. The analytical signal is calculated to delineate the source fields
of these anomalies. It dramatically maps the charnockites and is able to delineate the orthopyroxene isograd. In the Dharwar
region the magnetic signatures are associated with the intrusives/ iron ore bodies. Thus, we find that the source rocks of
the aeromagnetic anomalies are the host province of charnockites in the SGT and the intrusives/iron ore bodies in the Dharwar
belt. Gravity residuals are calculated and a tectonic map of the region is presented from the combined geopotential data. 相似文献
7.
弓长岭铁矿床物质来源及沉积古地理环境研究 总被引：1，自引：0，他引：1
弓长岭沉积变质型铁矿床是中国鞍山式铁矿床的典型代表.研究表明,该铁矿床赋存于反S型褶皱中,局部矿体出现褶曲现象.矿体产于主要由磁铁石英岩、斜长角闪岩、黑云母变粒岩和“蚀变岩”组成的含铁岩系中.文章通过研究该地区铁矿石的构造、结构和矿物组合,结合常量、微量及稀土元素研究,揭示了该地区形成铁矿床的物质来源与海底热液活动密切相关,在其形成过程中,很少或者没有含铝碎屑物质的加入,是由海洋化学沉积形成的,形成于还原环境.通过研究与铁矿床空间关系密切的斜长角闪岩、黑云母变粒岩和“蚀变岩”的构造和结构等,并利用常量、微量及稀土元素的测试结果,对斜长角闪岩、黑云母变粒岩和“蚀变岩”进行了原岩恢复研究,研究结果显示,该区斜长角闪岩的原岩应为洋中脊拉斑玄武岩,黑云母变粒岩的原岩应为大陆岛弧的杂砂岩,而“蚀变岩”的形成则与磁铁石英岩有着密切的关系.最后,提出了该地区铁矿床沉积的古地理环境为洋壳边缘、大陆岛弧附近,其形成环境应相当于弧后盆地. 相似文献
8.
《International Journal of Coal Geology》1986,6(3):251-276
The iron sulfides in seven different Ohio coals have been studied by polished-section ore microscopy, scanning electron microscopy augmented with EDS analyses, and secondary ion mass spectrometry. The iron sulfides in the coals exhibit a large array of textures and interrelationships which reflect site-specific environmental changes that occurred during the deposition of the sulfides. Sulfide deposition occurred principally during the depositional and diagenetic phases of the formation of the precursor peats. Pyrite and marcasite are present in most of the samples examined. Pyrite occurs as isolated and clustered euhedra, isolated and clustered framboids and spheres, cell-fillings, cleat- and fracture-fillings, replacements of plant debris, and as a porous or spongy-textured variety deposited within and around sulfide masses and grains. Marcasite occurs as polycrystalline spheres, polycrystalline rims and bands within and around clusters of pyrite spheres and framboids, as cell-fillings, and as replacements of plant debris. A typical sequence of iron sulfide deposition in texturally complex sulfide grains and masses is: (1) pyrite framboids or spheres; (2) deposition of marcasite around the relict framboids and clusters of framboids; and (3) spongy pyrite deposited as an outer fringe around sulfide masses and as infillings within the masses. The sulfides exhibit a persistent, although not universal, association with clays, and it is likely that much of the iron now present as sulfides was delivered to the depositional environment adsorbed on clay minerals. The iron sulfides tend to be localized in zones parallel to the banding in the coals. Such localization is most pronounced with respect to specific varieties of iron sulfides such as marcasite spheres, pyrite framboids, zones of pyrite euhedra, and occurrences of texturally complex grains and masses. Such zones are believed to represent depositional environments favorable for the precipitation of specific types of iron sulfides. These stratigraphic microenvironments changed during the times of deposition and diagenesis of the precursor peats and resulted in sequential deposition of the different forms of iron sulfides particularly evident in texturally complex sulfide grains. Chemically significant variables most likely were pH and availability of certain trace elements. The factors favoring precipitation of marcasite rather than pyrite are not clearly understood.The textures of the iron sulfides will prove to be important in understanding the reactivity of pyrite and marcasite in causing acid mine drainage and possibly spontaneous combustion of coal and mine waste, and will be important in the continuing development of effective methods of coal cleaning. 相似文献
9.
关键金属对于国家高精尖科技发展具有举足轻重的地位。近年来,随着科技革命推进和新兴产业发展,许多国家对关键金属资源的争夺愈加激烈。中国战略性关键金属与"四稀金属"大致对应,主要以伴生形式赋存于各种类型的矿床中。铁矿是中国分布最广泛、研究最成熟的金属矿产之一,但以往的研究主要注重于铁矿床类型及成因的研究,对其伴生的关键金属研究程度不够。文章通过对大量文献开展深入调研工作,系统地总结了中国铁矿床中关键金属的基本特征和时空分布规律,并初步评价了铁矿床中关键金属的资源潜力。研究结果显示,铁矿作为大宗金属矿产主要伴生REE、Sc、Nb、Ta、PGE、Co、Ni、Ga、Ge、Se、Cd、In、Te、Re等关键金属以及Mn、Ti、V等有色金属;中国伴生关键金属铁矿床主要划分为5个成矿区：扬子地台西缘成矿区、长江中下游成矿区、鲁西成矿区、华北准地台北缘成矿区和白乃庙-东升庙成矿区。对铁矿床中伴生关键金属的赋存状态和超常富集机制的深入研究,将为关键金属资源综合利用和找矿勘查提供参考,并提高中国战略性关键金属资源储备和国际竞争力。 相似文献
10.
E. L. BOARDMAN 《Sedimentology》1989,36(4):621-633
Blackband iron formations are essentially thin (approximately 0·75 m thick) siderite-rich (total iron up to 40%), carbonaceous, laminated mudrocks which commonly occur in grey coal bearing sequences in close proximity to coal seams. They exhibit a conspicuous laminated macrotexture made up of carbonaceous and siderite-rich laminae together with primary textures such as root-disturbed laminae, sideritized unflattened spores and preservation of plant cell detail. These all point to formation of siderite soon after deposition, in some cases before significant compaction. Their enclosing sediments clearly show that they were deposited in environments intermediate between delta top alluvial floodplains and coastal plain swamps in which small areas were subjected to periods of lacustrine deposition. The presence of varved mudrocks and oil shales in the beds directly above many of the blackband iron formations and the distinctive fine lamination of the blackbands are evidence of such depositional environments. The blackband iron formations are considered to have been formed in a similar way to Recent bog iron ores and are therefore interpreted as fossil bog iron ores. A model for their mode of formation is presented. 相似文献
11.
山东省齐河县境内发育有矽卡岩型铁矿,近年来该区铁矿勘查和研究工作取得了较大进展。本文通过对研究区内铁矿勘查研究成果进行统计分析,旨在对其控矿特征和找矿标志进行探讨来促进该区铁矿找矿工作。研究区内铁矿控矿地层为奥陶纪碳酸盐岩和石炭纪-二叠纪碎屑岩地层,成矿地质体为燕山晚期中基性侵入岩体;铁矿体主要赋存于地层和岩体的接触带处,且在碳酸盐岩、碎屑岩地层中和侵入岩体中也赋存有部分铁矿体。区内铁矿体赋存类型多样,其中以接触带赋存式为主,且含有断裂充填式、层间充填式、裂隙贯入式、捕虏体构造式等。铁矿体形态复杂,呈层状、似层状、囊状、透镜状等;矿床典型蚀变分带特征为闪长岩带-蚀变闪长岩带-内矽卡岩带-铁矿体-外矽卡岩带-大理岩化带-灰岩带。该区成矿作用以接触扩散交代作用、接触渗滤交代作用为主,此外还有富矿热液充填作用等。研究区内铁矿找矿标志主要包括地层标志（奥陶纪碳酸盐岩和石炭纪-二叠纪碎屑岩地层）、岩体标志（中基性侵入岩体,且发育有钠长石化的蚀变闪长岩）、构造标志（地层与岩体接触带、构造交汇部位、层间滑脱部位、脆性裂隙部位等）、围岩蚀变标志（磁铁矿化、矽卡岩化、钠长石化、蛇纹石化、金云母化等与成矿关系密切）、地球物理标志（明显的高值磁异常和化极磁异常部位、重力异常梯度带和高-低电阻转换带）。在今后铁矿勘查过程中,需要在综合研究该区控矿特征的基础上,可利用多种找矿标志进行相互配合、互为补充和综合研究,以期达到预期勘查效果。 相似文献
12.
索家沟银多金属矿床是近年来在内蒙古中南部发现的大型隐伏银多金属矿床,银多金属矿体主要赋存于燕山期酸性侵入岩体附近早期构造及同期张裂隙中,在岩体上部也发育矿化,属岩浆热液成因。为预测矿床深部找矿前景,笔者对矿床激电极化率异常、钻孔原生晕及深部地质体矿化特征进行研究。矿床频谱激电测量显示,激电极化率异常往深部未封闭且具较大延伸趋势;原生晕研究结果表明矿体叠加晕特征明显,局部出现反向分带特征,表明具有多阶段成矿的特征;同时Ag、Pb、Zn、Cu、Au、W、Sn等元素异常向深部均呈现高强度延伸,指示深部具备较好找矿潜力,由此提出深部存在厚大盲矿体或多金属矿脉群。通过对深部已控制岩体及Au、Cu矿化特征分析,提出深部具备寻找斑岩型铜金钨(钼)系列矿产的潜力。根据当前矿床地物化特征,认为索家沟银多金属矿床具有斑岩型成矿系统的特征,提出在岩体外围及浅部-中深部继续寻找银铅锌矿,深部寻找金铜钨(钼)矿的找矿方向,为该矿区或同类型区域进一步找矿提供借鉴。 相似文献
13.
莲花山铁矿位于昌邑-安丘铁成矿带的中部,铁矿体赋存于古元古代粉子山群小宋组中。本文通过矿石地球化学特征及其与矽卡岩矿物组合和赋矿围岩结构特征的对比研究,证明了莲花山铁矿与条带状铁矿相似。莲花山铁矿矿石稀土元素含量较低,经页岩标准化的稀土元素配分模式呈现轻稀土元素亏损、重稀土元素富集的特征,具有明显的Eu、Y、La异常,为无明显Ce异常,Y/Ho比值反映了在其沉积时受到海水作用的影响,表明莲花山铁矿的稀土元素来源于火山热液和海水的混合溶液。微量元素中Ti、V、Co、Ni、Mn、Sr、Ba等含量较低,原始地幔标准化的微量元素配分曲线显示,U、La、Hf呈正异常,Ba、Nb、Ta、Sr呈负异常,SiO2/Al2O3、Ti/V、Ni/Co、和Sr/Ba的比值指示了莲花山铁矿成矿物质来源于火山物质的沉积。研究结果表明,莲花山铁矿成矿作用源于火山热液与海水的混合,成矿物质来自火山沉积物,其地质与地球化学特征与五台山铁矿一致,为火山沉积变质型铁矿床。 相似文献
14.
The Okha Shell Limestone Member of Chaya Formation is the coarse grained, shell rich deposit commonly recognized as the beach
rocks. It has been age bracketed between Late Pleistocene and Holocene. Late Quaternary sea level changes have been studied
with beach rocks along the Saurashtra coastal region. The present study has been carried out in the Okhamandal area of the
Saurashtra peninsula especially on the Okha Shell Limestone Member as exposed at various locations along the coast from north
to south. Temporal and spatial correlations of the observations have revealed three events in the Okha Shell Limestone Member
of Chaya Formation that are correlated laterally. The events show depositional breaks represented by discontinuity surfaces,
the taphofacies varieties and ichnological variations. The present study in the context of available geochrnological data
of the region suggests a prominent depositional break representing low sea level stand (regression) during an Early Holocene
during the deposition of Okha Shell Limestone Member. 相似文献
15.
云南个旧锡矿是世界级超大型锡多金属矿床,层间矿床(锡石-硫化物)是其中重要的矿床类型之一,其成因也一直存在争议,为了进一步探讨其成因并对该类型矿床的深部勘查提供理论依据,重点对个旧锡矿高松矿田芦塘坝矿段10号矿群不同中段层间矿体的岩石矿物组构和地球化学特征进行了研究.结果表明层间矿床中的原生矿体多为块状硫化矿石,金属硫... 相似文献
16.
长江中下游地区铁、铜等成矿规律研究 总被引：29，自引：8，他引：29
本文反映了国家重点科技攻关项目75-55-02-01专题的地质研究成果,论文探讨了长江中下游区域成矿的地质背景和构造演化,提出燕山期本区为大陆板块内部的断块与裂陷交织的构造-岩浆-成矿带。燕山早期,以NWW—EW向为主的岩石圈断裂,控制了铜、钼、(金)矿带的分布;燕山晚期,以NNE—NE为主的岩石圈断裂,主要控制了铁及铁-铜矿带的分布。矿带内各矿田的位置,受基底构造和盖层构造的联合控制。根据环形构造、线性构造与侵入岩体的关系,建立了本区矿田构造垂直分带的“三层结构”模式。首次研究了主要赋矿层位——石炭系、二叠系、三叠系地球化学,包括有机碳含量及与金属成矿的关系。对中生代侵入岩的岩石化学和含矿性进行了系统研究,划分了3个成岩成矿亚系列。在综合研究区域构造、沉积、岩浆、成矿等作用演化的基础上,提出本区存在两个成矿系列,即沉积成矿系列(古生代为主)和岩浆成矿系列(燕山期为主),后者是本区主要的金属成矿系列。两个系列的叠加复合是本区区域成矿的一个特色,是造成矿床多样性和复合性的重要原因。论文讨论了铁矿带和铜矿带的区域分布及二者的相互关联,并论述了长江中下游成矿带在环太平洋矿带中的地位和特色。 相似文献
17.
新疆赞坎铁矿床位于西昆仑塔什库尔干地块西段,是近年新发现的一个大型沉积变质型磁铁矿床。赋矿岩系布伦阔勒群主要由黑云母石英片岩、斜长角闪片岩、变粒岩、硅质岩及磁铁石英岩等组成。目前探明工业矿体4条,单个矿体长度大于2.5km,矿体厚10~70m;局部见高品位铁矿段(mFe50%),长度达900m,厚度40m左右。矿石类型主要为2种,一种为原生的条纹-条带状磁铁矿(为主);另一种为热液改造形成的块状(高品位铁矿石)及浸染状磁铁矿。矿石稀土元素配分(PAAS)表明,原生条纹-条带状铁矿石Ce和Y元素异常不明显(~1.15、~0.94),Eu具正异常(~1.69),Y/Ho平均值为25,稀土配分模式与沉积变质型铁矿相似。而受改造的矿石中,浸染状矿石具有较高的稀土总量,明显富集轻稀土,La和Ce显示正异常(~1.46、~1.17),Y显示负异常(=0.66~0.72),Eu表现为强烈的正异常(~4.37),稀土配分模式明显不同于原生条纹-条带状铁矿石。矿体围岩斜长角闪片岩(变沉积岩)中的碎屑锆石U-Pb年龄为591±1Ma,结合前人对矿区内侵入体的年代学研究(霏细斑岩,533Ma),大致反映沉积铁矿的形成时代为新元古代至早寒武世。电子探针显示,条带状磁铁矿中的TiO_2、AL_2O_3、MgO、MnO含量较低,标型组分含量与沉积变质型磁铁矿颇为接近,在磁铁矿单矿物成因图解中,条带状磁铁矿整体显示磁铁矿为沉积变质型铁矿;浸染状矿石和块状矿石的组成与典型沉积变质型铁矿的偏离反映了后期岩浆-构造热事件对条带状铁矿石的改造;上述结果显示赞坎铁矿整体属于沉积变质型铁矿(BIF)。调查发现赞坎高品位铁矿体与早寒武世侵入的霏细斑岩联系密切,高品位矿石及其围岩发育一定程度的矽卡岩化,如阳起石化、碳酸盐化和黄铁矿化。本文推测高品位铁矿石的成因可能为霏细斑岩的岩浆热液溶解并运移早期沉积变质铁矿中的含铁物质,在构造发育处充填交代形成块状磁铁富矿石。在早寒武世侵入到矿区中部的霏细斑岩体中,同时发育有角砾状磁铁矿和脉状磁铁矿,因此,岩浆热液改造原生条带状铁矿石形成高品位铁矿石的时代应为早寒武世。 相似文献
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西天山智博铁矿床磁铁矿成分特征及其矿床成因意义 总被引：12，自引：7，他引：5
智博大型磁铁矿床位于新疆西天山阿吾拉勒成矿带东段,赋存于石炭系大哈拉军山组玄武质安山岩、安山岩及火山碎屑岩中。智博铁矿床包括东、中、西以及13号矿体4个矿段。矿体主要呈层状、似层状、透镜状。金属矿物以磁铁矿为主,含少量浸染状黄铁矿,局部可见细脉赤铁矿及零星状黄铜矿。矿石构造以块状和浸染状构造为主,角砾状次之,局部为条带状构造、脉状-网脉状构造;矿石结构包括半自形-他形粒状结构、交代残余结构、板条状结构。智博矿区的蚀变矿物组合以透辉石、钠长石、钾长石、绿帘石、阳起石为主,含有少量方解石、石英、绿泥石及榍石。根据矿物共生组合、矿石结构的观察以及矿物化学分析,识别出岩浆期和热液期2个成矿期,进一步细分为3个成矿阶段:磁铁矿-透辉石-绿帘石阶段(a1),磁铁矿-钾长石-绿帘石阶段(b1),石英-硫化物阶段(b2)。磁铁矿的电子探针成分分析显示,岩浆期矿石中FeOT含量较高,而Al2O3、CaO、MgO、SiO2等氧化物含量较低,热液期矿石则相反。角砾状和部分浸染状磁铁矿中V2O5含量相对较高,与火山岩中含量类似,暗示该矿化阶段的铁质部分来源于围岩;块状以及浸染状磁铁矿FeOT含量大部分在90%以上;角砾状、网脉状、树枝状矿石中磁铁矿的w(FeOT)分布相对比较集中,多数在90%~92%之间;纹层状矿石的w(FeOT)则变化于88%~92%之间,其CaO、SiO2等氧化物平均含量相对增加。TiO2-Al2O3-MgO图解和Ca+Al+Mn vs Ti+V图解均表明智博铁矿床的形成与火山活动和岩浆热液的交代作用有关。 相似文献
19.
V. A. Stepanov L. I. Rogulina A. V. Melnikov D. V. Yusupov 《Geology of Ore Deposits》2007,49(7):619-623
The Dambuki ore cluster of the Upper Amur region is characterized by numerous and high-grade gold placers. A few small primary deposits and occurrences of gold-quartz type were formerly considered to be the main source of placers. However, the study of widespread Early Cretaceous Cu- and Ni-bearing ultramafic intrusions has shown that gold occurring in primary Cu-Ni ores and products of their weathering practically does not differ from placer gold in morphology, fineness, or geochemical features. In both cases, elements typical of Cu-Ni ore (Cu, Fe, Pd, Ni, etc.) are detected as impurities of gold particles. These data indicate that the Au-and Pt-bearing Cu-Ni ore mineralization may be the main source of placer gold. This ore mineralization is genetically related to small pyroxenite-cortlandite sills and dikes, abundant in the Dambuki ore cluster. The primary gold-quartz deposits and occurrences also contributed to the placers, but their part was rather small. 相似文献
20.
青海省东昆仑成矿带铁矿成矿规律与找矿方向研究 总被引：4，自引：0，他引：4
东昆仑成矿带位于西域板块南缘活动带与华南板块接合部位,属昆祁秦缝合系的昆仑缝合带。区内由昆北、昆中及昆南三条呈近东西向到北西西向平行展布的区域深大断裂,构成东昆仑复杂的构造格局,由此划分出三大构造成矿单元,即东昆仑北带、中带、南带。这三条大断裂均为切穿地壳或岩石圈的区域性长期活动深大断裂,不仅构成各地质单元的边界和控制岩浆岩分布,也控制了东昆仑隆起、凹陷带沉积盆地及沉积建造的展布,与次级北西、北北西向和北东向断裂一起,把不同时代地层和部分岩体切割成规模不等的断块(条),同时不同级次的断裂构造作为成矿的导矿场和储矿场,为各类矿床的形成提供了良好的迁移通道和赋存空间。该区地层主要集中发育在前寒武纪、早古生界奥陶―志留纪、晚古生代石炭―二叠纪、中生界三叠纪及新生代几个时间段中。在区域分布上,昆中、昆北带出露地层较相近,昆南带与昆北和昆中带有显著差异,反映为不同地层分区。岩浆活动非常强烈而频繁,分布亦十分广泛,主要分布在昆仑山北坡断隆带和祁漫塔格地区,在昆仑山主脊形成著名的东昆仑山花岗岩带,昆仑山南坡出露少量中酸侵入岩。岩浆活动始于元古代,止于新生代,表现为间歇性的火山喷发与岩浆侵入频繁交替。岩性从基性、超基性到酸性均有出露。主要活动时代为加里东期、华力西期,其次为印支期、燕山期;兴凯期和前兴凯期主要以少量基性、超基性喷流活动。东昆仑成矿带是青海重要成矿带之一,东昆仑成矿带侵入岩、褶皱、断裂构造发育,岩浆活动频繁强烈,成矿地质条件十分优越,具有较大找矿潜力。该带也是青海省主要的工业矿床集中分布的地区,储量大,品位较高,矿产地集中,同时共伴生的多金属矿床也往往具有一定的规模。尤其是矽卡岩型和沉积变质型铁矿的绝大多数储量都集中在本带。铁矿床成因类型复杂多样,主要有与火山喷流沉积有关的喷流——沉积、热液交代变质改造型,沉积变质型和矽卡岩型,具备大型——超大型矿床的成矿条件。矿床多沿昆北、昆中和昆南深大断裂带分布,与次级构造及岩浆岩体关系密切。东昆仑西段是重要的大——超大型矿床找矿远景区,中段具有沉积变质型铁矿找矿前景,东段则是矽卡岩型铁矿床聚集区。该带铁矿资源量占全省的75.51%,铁矿共、伴生有用组分较多,可综合利用。接触交代型铁矿是目前开发的重点,此类型矿石质量较好,TFe品位一般在35%～55%,有害杂质硫、磷一般低于工业要求。特别是都兰、野马泉地区的铁矿多共、伴生有铅、锌、铜、金、银、锡、钴、铋、镉、硫铁矿等有益元素,需综合开发利用。由于共、伴生组分可综合利用,极大地提高了开发价值。 相似文献